The basic aim of this work is to enhance the spatial resolution and tissue density discrimination ability of pulse echo ultrasound imaging by using signal processing techniques. The tissue density discrimination ability and also the spatial resolution are reduced in the depth direction primarily by the source waveform. Three signal deconvolution techniques - namely, constrained least-squares filtering, Wiener filtering, and inverse filtering - were extensively compared with regard to their ability to eliminate the effects of the source waveform. We have concluded that of these three techniques, constrained least-squares filtering is the best. Our proposed work in this area will involve including other deconvolution techniques in our comparison. We also propose to develop two-dimensional signal processing techniques that would, in one step, reduce both the source waveform effects and the transducer aperture effects. Transducer aperture is the primary limiting factor as far as lateral resolution is concerned.